Here, with a I5-2400, about 10% slower then yours, per core, it must have taken 12+ plus hours to compile Qt5, mostly the webengine, had to stop due to memory issues a few times. For comparison, Mozilla takes just over a 100 minutes.
Another thing that can slow things down, depending on video card, is drawing to the cmd window. You might try minimizing it or redirecting stdout to a file. Stderr will still show build breaks or watch the CPU meter.